The use of the liquid membrane technology, for example, see U.S. Pat. No. 3,779,907, in the preparation of products wherein the liquid membrane acts as a barrier for the release of an active ingredient is disclosed in U.S. Ser. No. 271,398, filed July 13, 1972, and U.S. Ser. No. 293,028, filed Sept. 28, 1972, herein incorporated by reference. These materials while suitable for the purposes disclosed in these patent applications suffer from one disadvantage, that is since the compositions are three phase emulsions, i.e., multiple emulsions, they have limited stability. After a period of time which in some instances may be less than minutes these materials separate into an emulsion phase, that is the desired structure of the compositions, i.e. emulsion droplets suspended in a continuous phase, is lost and the emulsion droplets coalesce and form a continuous emulsion either floating on or beneath the original continuous phase. One method which has been disclosed in these patent applications for improving the stability of the desirable multiple emulsion structure comprises adjusting the specific gravity of the continuous phase and the emulsion droplets so that they are equivalent. It will readily be appreciated by those skilled in the art that this is difficult and in certain cases impossible.
The compositions of this invention are characterized as stable multiple emulsions. These compositions are further characterized as pourable although in some variations the system may be gelled. Gelled systems however are not desirable.
Various other workers in the art have used multiple emulsions in processes for preparing emulsions encapsulated in solid capsules. During the preparation of this encapsulated emulsion, a three phase emulsion, i.e., a multiple emulsion, exists which comprises droplets of emulsion suspended in a continuous phase. This system however only exists while under the influence of agitation. for the purposes of the invention disclosed in these patents, this is sufficient since the continuous phase and/or the interface of the external phase of the emulsion and said continuous phase is converted into a solid capsule. Thus when agitation is terminated solid capsules are obtained. The instant compositions differ from the compositions taught therein in that solid capsules are not desired nor obtained.